Head-mounted display, information processing device, display control method, and program

ABSTRACT

A head-mounted display that displays an image representing appearance obtained when an object is viewed from a point of view disposed in a virtual three-dimensional space, includes a detecting section that detects rotation of the head-mounted display and a display control section that carries out control to cause displaying of an image representing appearance obtained when the object is viewed from the point of view that has relatively revolved in the direction of the detected rotation while the position of a point of gaze is kept in response to the detection of the rotation by the detecting section.

BACKGROUND

The present disclosure relates to a head-mounted display, an informationprocessing device, a display control method, and a program.

Portable game systems and game devices that include an accelerationsensor and so forth and can change displayed contents through change inthe posture are known (refer to Japanese Patent Laid-open Nos.2003-334379, 2003-325974, 2006-68027, and 2006-110382, which arehereinafter referred to as Patent Documents 1, 2, 3, and 4,respectively). In a technique described in Patent Documents 1 and 2, thebasic coordinates of the point of view are rotated in the oppositedirection to a tilt direction detected by a tilt sensor, and therefore,a player can be given a feeling as if a three-dimensional game spacewere tilted in association with the tilt of a game device or the like.

Furthermore, a head-mounted display (HMD) is known that is mounted at ahead by a user and allows the user to achieve visual sensing and soforth of an image representing appearance obtained when an object isviewed from a point of view disposed in a virtual three-dimensionalspace. Among such HMDs is one in which the position and the direction ofthe line of sight of the point of view disposed in the virtualthree-dimensional space change in association with change in the postureof the head of the user. For example, when the user moves the headwithout rotating the head, the position of the point of view moves inthe direction in which the head is moved while the direction of the lineof sight of the point of view disposed in the virtual three-dimensionalspace is kept. Furthermore, for example, when the user rotates the headwithout changing the position of the head, the direction of the line ofsight is rotated in the direction in which the head is rotated while theposition of the point of view disposed in the virtual three-dimensionalspace is kept.

SUMMARY

In the case of the related-art HMD, to visually sense, from variousangles, an object that appears to be disposed on the front side asviewed from the user in the virtual three-dimensional space, the usermakes the head revolve to various positions around the position in thereal space corresponding to the position of this object. For example, tovisually sense this object from the opposite side, the user goes aroundto the back side of the position in the real space corresponding to theposition of this object. As just described, in the case of therelated-art HMD, it is difficult to say that the burden on the user issmall when the user visually senses, from various angles, the objectthat appears to be disposed on the front side as viewed from the userand is disposed in the virtual three-dimensional space.

Possibly the technique described in Patent Documents 1 and 2 will beapplied to a situation in which a display unit is disposed in front ofthe eyes of a user irrespective of the posture of the head, such as asituation in which an HMD is mounted for example. However, in thistechnique, the basic coordinates of the point of view are rotated in theopposite direction to a tilt direction detected by the tilt sensor asdescribed above. Therefore, the user feels a sense of discomfort whenthis technique is applied to the situation in which a display unit isdisposed in front of the eyes of the user irrespective of the posture ofthe head.

It is desirable to alleviate the burden on a user when the user visuallysenses, from various angles, an object that appears to be disposed onthe front side as viewed from the user in a virtual three-dimensionalspace.

According to an embodiment of the present disclosure, there is provideda head-mounted display that displays an image representing appearanceobtained when an object is viewed from a point of view disposed in avirtual three-dimensional space. The head-mounted display includes adetecting section configured to detect rotation of the head-mounteddisplay and a display control section configured to carry out control tocause displaying of an image representing appearance obtained when theobject is viewed from the point of view that has relatively revolved inthe direction of the detected rotation while the position of a point ofgaze is kept in response to the detection of the rotation by thedetecting section.

According to another embodiment of the present disclosure, there isprovided an information processing device that displays an imagerepresenting appearance obtained when an object is viewed from a pointof view disposed in a virtual three-dimensional space. The informationprocessing device includes a display control section configured to carryout control to cause displaying of an image representing appearanceobtained when the object is viewed from the point of view that hasrelatively revolved in the direction of detected rotation while theposition of a point of gaze is kept in response to detection of therotation.

According to another embodiment of the present disclosure, there isprovided a display control method for displaying an image representingappearance obtained when an object disposed in a virtualthree-dimensional space is viewed from a point of view disposed in thevirtual three-dimensional space. The display control method includesdetecting rotation and carrying out control to cause displaying of animage representing appearance obtained when the object is viewed fromthe point of view that has relatively revolved in the direction of thedetected rotation while the position of a point of gaze is kept inresponse to the detection of the rotation.

According to another embodiment of the present disclosure, there isprovided a program for a computer which displays an image representingappearance obtained when an object disposed in a virtualthree-dimensional space is viewed from a point of view disposed in thevirtual three-dimensional space. The program includes, by a detectingsection, detecting rotation; and by a display control section, carryingout control to cause displaying of an image representing appearanceobtained when the object is viewed from the point of view that hasrelatively revolved in the direction of the detected rotation while theposition of a point of gaze is kept in response to the detection of therotation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing one example of the overall configuration ofone embodiment of the present disclosure;

FIG. 2 is a diagram showing one example of the configuration of ahead-mounted display according to one embodiment of the presentdisclosure;

FIG. 3 is a diagram showing one example of a virtual three-dimensionalspace;

FIG. 4 is a diagram showing one example of the relationship between therotation of the head and change in displayed contents;

FIG. 5 is a diagram showing one example of the virtual three-dimensionalspace;

FIG. 6 is a diagram showing one example of the movement of the head;

FIG. 7 is a diagram showing one example of the virtual three-dimensionalspace;

FIG. 8 is a diagram showing one example of change in displayed contentswhen the head moves;

FIG. 9 is a functional block diagram showing one example of functionsimplemented in the head-mounted display according to one embodiment ofthe present disclosure;

FIG. 10 is a diagram showing one example of the flow of processingexecuted in the head-mounted display according to one embodiment of thepresent disclosure;

FIG. 11 is a diagram showing one example of the movement of the head;

FIG. 12 is a diagram showing one example of the virtualthree-dimensional space;

FIG. 13 is a diagram showing one example of the virtualthree-dimensional space;

FIG. 14 is a diagram showing one example of change in displayed contentswhen the head moves;

FIG. 15 is an explanatory diagram for explaining one example of changeof a menu object according to the distance between the point of view andthe menu object and limitation of the range in which the point of viewcan move; and

FIG. 16 is an explanatory diagram for explaining one example of therotation of the menu object.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

One embodiment of the present disclosure will be described below withreference to the drawings.

FIG. 1 is a diagram showing one example of the overall configuration ofone embodiment of the present disclosure. FIG. 2 is a diagram showingone example of the configuration of a head-mounted display (HMD) 10according to the present embodiment. As shown in FIG. 1, the HMD 10 cancommunicate with a controller 12 in the present embodiment. Then, a userof the HMD 10 can carry out various kinds of operation to the HMD 10 byoperating the controller 12.

As shown in FIG. 2, a control unit 20, a storing unit 22, acommunication unit 24, a display unit 26, and a sensor unit 28 areincluded in the HMD 10 according to the present embodiment for example.

The control unit 20 is a program control device such as a centralprocessing unit (CPU) that operates in accordance with a program storedin the storing unit 22 for example.

The storing unit 22 is e.g. a memory element such as a read only memory(ROM) or a random access memory (RAM). In the storing unit 22, programsto be executed by the control unit 20 and so forth are stored.

The communication unit 24 is e.g. a communication interface such as awireless local area network (LAN) port. The communication unit 24according to the present embodiment receives an operation signaltransmitted from the controller 12 for example.

The display unit 26 is e.g. a display such as a liquid crystal displayor an organic electro-luminescence (EL) display and displays images,video, and so forth. In the present embodiment, the display unit 26 isdisposed in front of the eyes of a user who wears the HMD 10 as shown inFIG. 1. The display unit 26 according to the present embodiment may becapable of displaying three-dimensional video.

The sensor unit 28 is e.g. a sensor such as an acceleration sensor, agyro sensor, a geomagnetic sensor, or a barometric sensor and measuresthe posture, the amount of rotation, the amount of movement, and soforth of the HMD 10.

The sensor unit 28 according to the present embodiment outputs themeasurement results such as the posture, the amount of rotation, and theamount of movement of the HMD 10 to the control unit 20 at apredetermined frame rate (e.g. interval of 1/60 seconds). On the basisof these measurement results, the control unit 20 identifies the amountof movement and the amount of rotation of the HMD 10 per unit time, i.e.the speed and the angular velocity of the HMD 10. In this manner, theamount of movement and the amount of rotation of the HMD 10 can beidentified at the predetermined frame rate in the present embodiment.Furthermore, in the present embodiment, on the basis of the amount ofmovement and the amount of rotation that are identified, the positionand the direction of the line of sight of a point 30 of view in avirtual three-dimensional space change at the predetermined frame rateas described below.

The display unit 26 of the HMD 10 according to the present embodimentdisplays an image representing appearance obtained when an objectdisposed in a virtual three-dimensional space exemplified in FIG. 3 isviewed from the point 30 of view disposed in this virtualthree-dimensional space. In the virtual three-dimensional spaceexemplified in FIG. 3, a menu object 32 that is a hexahedron is disposedas one example of such an object. On each surface of the menu object 32according to the present embodiment, an option 34 for which any alphabetamong “A” to “F” is indicated is disposed. Here, for example, supposethat the option 34 of “A” is disposed on the front surface of the menuobject 32 and the option 34 of “B” and the option 34 of “C” are disposedon the upper surface and the right side surface, respectively.Furthermore, suppose that the option 34 of “D” is disposed on the backsurface of the menu object 32 and the option 34 of “E” and the option 34of “F” are disposed on the lower surface and the left side surface,respectively, although these options 34 are not clearly shown in FIG. 3.

In the present embodiment, for example, in the initial state, the point30 of view is disposed at a position P1 in the virtual three-dimensionalspace, with the direction of the line of sight oriented toward theoption 34 of “A,” as shown in FIG. 3. Therefore, in the presentembodiment, the option 34 of “A” is displayed on the display unit 26 inthe initial state for example.

Furthermore, in the present embodiment, a point 36 of gaze is set at thecenter of the menu object 32 as shown in FIG. 3 in the initial state forexample. Moreover, the direction of the line of sight of the point 30 ofview passes through the point 36 of gaze in the initial state. Here,suppose that the point 36 of gaze is set at a position P0 for example.

In the virtual three-dimensional space shown in FIG. 3, the direction ofthe line of sight in the initial state is defined as the X-axis positivedirection. Furthermore, the right direction as viewed from the point 30of view in the initial state is defined as the Y-axis positive directionand the upper direction as viewed from the point 30 of view in theinitial state is defined as the Z-axis positive direction.

In the present embodiment, a user who wears the HMD 10 can change thedisplayed option 34 by rotating the head. Furthermore, in the presentembodiment, in response to selection operation by the user, processingaccording to the option 34 being displayed when the selection operationis carried out, specifically e.g. initiation of a game programassociated with the option 34 being displayed, displaying of a settingscreen, or the like, is executed.

In the present embodiment, when the user who wears the HMD 10 rotatesthe head, the point 30 of view relatively revolves in the direction ofthe rotation. Furthermore, in the present embodiment, the position ofthe point 36 of gaze and the distance from the point 30 of view to themenu object 32 are kept when the point 30 of view revolves.

Here, suppose that the user rotates the head to orient the face towardthe lower side as shown in column A of (1) of FIG. 4 when the point 30of view is disposed at the position P1. In this case, the point 30 ofview revolves to a position P2 along a route R1 so that the direction ofthe line of sight may be oriented toward the lower side as shown in FIG.3. Here, for example, the point 30 of view revolves on the XZ plane by90 degrees clockwise as viewed from the right side of the virtualthree-dimensional space in FIG. 3, i.e. as viewed along the Y-axisnegative direction. Thereupon, as shown in column B of (1) of FIG. 4,the option 34 displayed on the display unit 26 changes from “A” to “B.”

Suppose that the user rotates the head to orient the face toward theleft side as shown in column A of (2) of FIG. 4 when the point 30 ofview is disposed at the position P1. In this case, the point 30 of viewrevolves to a position P3 along a route R2 so that the direction of theline of sight may be oriented toward the left side as shown in FIG. 3.Here, for example, the point 30 of view revolves on the XY plane by 90degrees anticlockwise as viewed from the upper side of the virtualthree-dimensional space in FIG. 3, i.e. as viewed along the Z-axisnegative direction. Thereupon, as shown in column B of (2) of FIG. 4,the option 34 displayed on the display unit 26 changes from “A” to “C.”

Suppose that the user rotates the head anticlockwise as viewed fromabove to orient the face toward the back side as shown in column A of(3) of FIG. 4 when the point 30 of view is disposed at the position P1.In this case, the point 30 of view revolves to a position P4 along theroute R2 and a route R3 so that the direction of the line of sight maybe oriented toward the back side as shown in FIG. 3. Here, for example,the point 30 of view revolves on the XY plane by 180 degreesanticlockwise as viewed from the upper side of the virtualthree-dimensional space in FIG. 3, i.e. as viewed along the Z-axisnegative direction. Thereupon, as shown in column B of (3) of FIG. 4,the option 34 displayed on the display unit 26 changes from “A” to “D.”

Suppose that the user rotates the head to orient the face toward theupper side as shown in column A of (4) of FIG. 4 when the point 30 ofview is disposed at the position P1. In this case, the point 30 of viewrevolves to a position P5 along a route R4 so that the direction of theline of sight may be oriented toward the upper side as shown in FIG. 3.Here, for example, the point 30 of view revolves on the XZ plane by 90degrees anticlockwise as viewed from the right side of the virtualthree-dimensional space in FIG. 3, i.e. as viewed along the Y-axisnegative direction. Thereupon, as shown in column B of (4) of FIG. 4,the option 34 displayed on the display unit 26 changes from “A” to “E.”

Suppose that the user rotates the head to orient the face toward theright side as shown in column A of (5) of FIG. 4 when the point 30 ofview is disposed at the position P1. In this case, the point 30 of viewrevolves to a position P6 along a route R5 so that the direction of theline of sight may be oriented toward the right side as shown in FIG. 3.Here, for example, the point 30 of view revolves on the XY plane by 90degrees clockwise as viewed from the upper side of the virtualthree-dimensional space in FIG. 3, i.e. as viewed along the Z-axisnegative direction. Thereupon, as shown in column B of (5) of FIG. 4,the option 34 displayed on the display unit 26 changes from “A” to “F.”

Suppose that the user rotates the head clockwise as viewed from above toorient the face toward the back side as shown in column A of (6) of FIG.4 when the point 30 of view is disposed at the position P1. In thiscase, the point 30 of view revolves to the position P4 along the routeR5 and a route R6 so that the direction of the line of sight may beoriented toward the back side as shown in FIG. 3. Here, for example, thepoint 30 of view revolves on the XY plane by 180 degrees clockwise asviewed from the upper side of the virtual three-dimensional space inFIG. 3, i.e. as viewed along the Z-axis negative direction. Thereupon,as shown in column B of (6) of FIG. 4, the option 34 displayed on thedisplay unit 26 changes from “A” to “D.”

As described above, in the present embodiment, according to the rotationof the head of the user who wears the HMD 10, the point of viewrelatively revolves in the direction of the rotation of the head of theuser, with the position of the point 36 of gaze kept. Therefore, theuser can effortlessly visually sense, from every angle, the object thatappears to be disposed on the front side as viewed from the user and isdisposed in the virtual three-dimensional space. In this manner,according to the present embodiment, the burden on the user when theuser visually senses the object that appears to be disposed on the frontside as viewed from the user and is disposed in the virtualthree-dimensional space is alleviated.

Furthermore, the operation of the HMD 10 according to the presentembodiment is obviously different from the operation of the HMDaccording to the related-art virtual reality (VR) technique in which theposition and the direction of the line of sight of a point of viewdisposed in a virtual three-dimensional space change in association withchange in the posture of the head of the user. Nevertheless, change indisplaying in the HMD 10 according to the present embodiment when thehead is made to revolve around the position in the real spacecorresponding to the position of the menu object 32 is similar to changein displaying in the HMD according to the related-art VR technique.Therefore, even a user who is accustomed to the HMD according to therelated-art VR technique can use the HMD 10 according to the presentembodiment without a sense of discomfort.

In the present embodiment, when the point 30 of view revolves, not onlythe position of the point 36 of gaze but also the distance from thepoint 30 of view to the menu object 32 is also kept. Therefore, the usercan visually sense the menu object 32 more effortlessly than in the casein which the distance from the point 30 of view to the menu object 32 isnot kept.

As shown in FIG. 5, the menu object 32 may rotate according to therotation of the head of the user in place of the revolution of the point30 of view in the direction of the rotation of the head of the user. Inthis case, the positions of the point 30 of view and the menu object 32may be kept. Also in this case, relatively the point 30 of view revolvesin the direction of the rotation of the head of the user, with theposition of the point of gaze kept. The point is that it suffices thatthe rotation of the menu object 32 is displayed, and the revolution ofthe point 30 of view and the rotation of the menu object 32 areequivalent as displaying at the time of the rotation of the head.

In the above description, the angle by which the head of the userrotates corresponds with the angle by which the point 30 of viewrevolves. However, the angle by which the head of the user rotates doesnot have to correspond with the angle by which the point 30 of viewrevolves. For example, the point 30 of view may revolve by the angletwice the angle by which the head of the user rotates.

In the present embodiment, when the user who wears the HMD 10 moves thehead left or right, the point 30 of view and the point 36 of gazerelatively move in the direction of the movement of the head. Thedistance of the movement of the point 30 of view and the point 36 ofgaze may be proportional to the distance of the movement of the head ofthe user. Furthermore, in the present embodiment, the point 36 of gazemoves in the same direction by the same distance as the point 30 ofview. Here, for example, suppose that the head of the user is disposedat a position P7 in the real space as shown in FIG. 6. Furthermore,suppose that the point 30 of view is disposed at the position P3 asshown in FIG. 7 when the head of the user is disposed at the positionP7. In addition, suppose that the direction of the line of sight of thepoint 30 of view is oriented toward the point 36 of gaze set at theposition P0. Moreover, suppose that the option 34 of “C” is displayed onthe display unit 26 as shown at the center of FIG. 8.

Suppose that, from the state in which the head of the user is disposedat the position P7 as shown in FIG. 6, the head of the user moves leftfrom the position P7 to a position P8 along a route R7 for example. Inthis case, the point 30 of view moves left from the position P3 to aposition P10 along a route R9 as shown in FIG. 7. Furthermore, the point36 of gaze moves left from the position P0 to a position P11 along aroute R10. Thereupon, as shown on the left side of FIG. 8, the menuobject 32 displayed on the display unit 26 moves right.

Suppose that, from the state in which the head of the user is disposedat the position P7 as shown in FIG. 6, the head of the user moves rightfrom the position P7 to a position P9 along a route R8 for example. Inthis case, the point 30 of view moves right from the position P3 to aposition P12 along a route R11 as shown in FIG. 7. Furthermore, thepoint 36 of gaze moves right from the position P0 to a position P13along a route R12. Thereupon, as shown on the right side of FIG. 8, themenu object 32 displayed on the display unit 26 moves left.

In the above-described manner, in the present embodiment, the user canrelatively move the position of the point 30 of view left or right bymoving the head left or right. Furthermore, similarly, the position ofthe point 30 of view may relatively move in the front-rear direction orthe upward-downward direction when the user moves the head in thefront-rear direction or the upward-downward direction. The position ofthe menu object 32 may be moved instead of moving the positions of thepoint 30 of view and the point 36 of gaze.

When the user moves the head upward, downward, left, or right, the HMD10 according to the present embodiment may enter an upward-downwardleft-right movement mode in which the respective surfaces of the menuobject 32 are displayed according to the amount of movement until theuser rotates the head subsequently. In the upward-downward left-rightmovement mode, the displayed surface of the menu object 32 may change tothe upper or lower next surface every time upward or downward movementof the head beyond a predetermined amount of movement is performed forexample. Furthermore, the displayed surface of the menu object 32 maychange to the left or right next surface every time leftward orrightward movement of the head beyond a predetermined amount of movementis performed for example. Then, when the user rotates the headsubsequently, the HMD 10 may make transition to a rotation mode inwhich, in response to the rotation of the head, the point of viewrelatively revolves in the direction of the rotation of the head of theuser, with the position of the point 36 of gaze kept.

A further description will be made below about the functions of the HMD10 according to the present embodiment and the processing executed inthe HMD 10 according to the present embodiment.

FIG. 9 is a functional block diagram showing one example of functionsimplemented in the HMD 10 according to the present embodiment. In theHMD 10 according to the present embodiment, all of the functions shownin FIG. 9 do not need to be implemented and a function other than thefunctions shown in FIG. 9 may be implemented.

As shown in FIG. 9, the HMD 10 according to the present embodimentincludes a point-of-view data storing section 40, a detecting section42, a point-of-view control section 44, an operation accepting section46, a display control section 48, and a processing executing section 50in terms of functions for example. The point-of-view data storingsection 40 is implemented on the basis mainly of the storing unit 22.The detecting section 42 is implemented on the basis mainly of thecontrol unit 20 and the sensor unit 28. The point-of-view controlsection 44 and the processing executing section 50 are implemented onthe basis mainly of the control unit 20. The operation accepting section46 is implemented on the basis mainly of the communication unit 24. Thedisplay control section 48 is implemented on the basis mainly of thecontrol unit 20 and the display unit 26.

The above functions are implemented by execution of a program that isinstalled in the HMD 10 as a computer and includes commandscorresponding to the above functions by the control unit 20. Thisprogram is supplied to the HMD 10 via a computer-readable informationstorage medium such as an optical disk, magnetic disk, magnetic tape,magneto-optical disk, or flash memory or via the Internet or the like.

The point-of-view data storing section 40 stores data indicating theposition and the direction of the line of sight of the point 30 of view.Suppose that, in the present embodiment, point-of-gaze position dataindicating the coordinate value of the position of the point 36 of gazein the virtual three-dimensional space and point-of-view vector dataindicating a vector having the position of the point 36 of gaze as thestart point and the position of the point 30 of view as the end pointare stored in the point-of-view data storing section 40 for example. Theposition and the direction of the line of sight of the point 30 of viewmay be managed on the basis of the position of the point 36 of gaze andthe vector having the position of the point 36 of gaze as the startpoint and the position of the point 30 of view as the end point as justdescribed.

In the present embodiment, the detecting section 42 detects the rotationof the HMD 10 for example.

Furthermore, the detecting section 42 also detects the movement of theHMD 10 in the present embodiment. In the present embodiment, thedetecting section 42 detects the amount of movement and the amount ofrotation of the HMD 10 at a predetermined frame rate on the basis of ameasurement result output by the sensor unit 28 for example. Here, forexample, the amount of movement is identified on the basis of ameasurement result of an acceleration sensor and the amount of rotationis identified on the basis of a measurement result of a gyro sensor.

In the present embodiment, the point-of-view control section 44 carriesout control to cause change in the position and the direction of theline of sight of the point 30 of view on the basis of the amount ofmovement and the amount of rotation detected by the detecting section 42for example. In response to detection of the rotation of the HMD 10, thepoint-of-view control section 44 causes the point 30 of view torelatively revolve in the direction of the detected rotation, with theposition of the point 36 of gaze kept, as described with reference toFIGS. 3 to 5 for example. The point-of-view control section 44 may causethe point 30 of view to revolve while the position of the point 36 ofgaze and the distance between the point 30 of view and the object arekept. Furthermore, the point-of-view control section 44 may carry outcontrol to cause the point 30 of view to relatively move in response todetection of the movement of the HMD 10 as described with reference toFIGS. 6 to 8. Specifically, the point-of-view control section 44 updatesthe coordinate value and the vector indicated by the point-of-gazeposition data and the point-of-view vector data, respectively, stored inthe point-of-view data storing section 40 on the basis of the amount ofmovement and the amount of rotation detected by the detecting section 42for example.

In the present embodiment, for example, in response to operation by auser to the controller 12, the operation accepting section 46 accepts anoperation signal associated with this operation from the controller 12.

In the present embodiment, for example, in response to detection ofrotation by the detecting section 42, the display control section 48carries out control to cause the display unit 26 to display an imagerepresenting appearance obtained when the object is viewed from thepoint 30 of view that has relatively revolved in the direction of thedetected rotation while the position of the point 36 of gaze is kept. Inthe present embodiment, an image representing appearance obtained whenthe menu object 32 is viewed from the point 30 of view whose positionand direction of the line of sight have been controlled by thepoint-of-view control section 44 is displayed on the display unit 26 forexample.

In the present embodiment, for example, the processing executing section50 executes processing according to the option disposed on the surfaceof the object displayed on the display unit 26 in response to acceptanceof selection operation as described above.

One example of the flow of display control processing executed in theHMD 10 according to the present embodiment at a predetermined frame ratewill be described with reference to a flow diagram exemplified in FIG.10. Suppose that the menu object 32 is disposed in a virtualthree-dimensional space in the processing example shown in FIG. 10.

First, the detecting section 42 identifies the amount of movement andthe amount of rotation of the HMD 10 in the period from theimmediately-previous frame to the relevant frame (S101).

Then, the point-of-view control section 44 decides the positions of thepoint 30 of view and the point 36 of gaze in the relevant frame on thebasis of the amount of movement and the amount of rotation identified inthe processing shown in S101 (S102).

In the processing shown in S102, the coordinate value and the vectorindicated by the point-of-gaze position data and the point-of-viewvector data, respectively, stored in the point-of-view data storingsection 40 are updated for example. Specifically, for example, thecoordinate value indicated by the point-of-gaze position data stored inthe point-of-view data storing section 40 is updated to a value obtainedby adding, to this coordinate value, a value obtained by multiplying thevalue of the amount of movement identified in the processing shown inS101 by a predetermined coefficient. Furthermore, the vector indicatedby the point-of-view vector data stored in the point-of-view datastoring section 40 is updated to a vector in a direction resulting fromrotation of the vector indicated by the point-of-view vector data aroundthe start point according to the amount of rotation identified in theprocessing shown in S101. The angle by which the vector indicated by thepoint-of-view vector data is rotated may be an angle obtained bymultiplying the angle represented by the amount of rotation identifiedin the processing shown in S101 by a predetermined factor for example.

Then, the display control section 48 causes the display unit 26 todisplay an image representing appearance obtained when a look is takenfrom the position of the point 30 of view decided in the processingshown in S102 toward the position of the point 36 of gaze decided in theprocessing shown in S102 (S103). In this processing example, thecoordinate value of the position of the point 36 of gaze in the relevantframe is equivalent to the coordinate value indicated by thepoint-of-gaze position data resulting from the update by the processingshown in S102. Furthermore, the coordinate value of the position of thepoint 30 of view in the relevant frame is equivalent to the coordinatevalue of the position resulting from movement of the position indicatedby the point-of-gaze position data resulting from the update by theprocessing shown in S102 by the vector indicated by the point-of-viewvector data resulting from the update in the processing shown in S102.

In this processing example, the processing shown in S101 to S103 isrepeatedly executed at a predetermined frame rate as described above. Inthis manner, in the present embodiment, the image displayed on thedisplay unit 26 is updated at the predetermined frame rate in such amanner as to follow the rotation and movement of the head.

In the present embodiment, when the point 30 of view moves forward orrearward, the object disposed in the virtual three-dimensional space maychange according to change in the distance between the point 30 of viewresulting from the movement and the object disposed in the virtualthree-dimensional space. A description will be made below about changein the object disposed in the virtual three-dimensional space accordingto change in the distance between the point 30 of view and this object.

Here, for example, suppose that the head of a user is disposed at aposition P14 in the real space as shown in FIG. 11. Furthermore, supposethat the point 30 of view is disposed at the position P3 as shown inFIGS. 12 and 13 when the head of the user is disposed at the positionP14. Moreover, the direction of the line of sight of the point 30 ofview is oriented toward the point 36 of gaze set at the position P0. Inaddition, suppose that the option 34 of “C” is displayed on the displayunit 26 as shown at the center of FIG. 14.

Suppose that, from the state in which the head of the user is disposedat the position P14 as shown in FIG. 11, the head of the user movesforward from the position P14 to a position P15 along a route R13 forexample. In this case, the point 30 of view moves forward from theposition P3 to a position P17 along a route R15 as shown in FIG. 12.Then, the menu object 32 disposed in the virtual three-dimensional spacechanges to a menu object 60 shown in FIG. 12. This leads to displayingof the menu object 60 on the display unit 26 as shown on the upper sideof FIG. 14.

The menu object 60 shown in FIG. 12 is a hexahedron as with the menuobject 32, and four options 62 are disposed on each surface.Furthermore, the surfaces of the menu object 60 are each associated withany surface of the menu object 32. The surface of the menu object 60 andthe surface of the menu object 32 associated with each other areoriented in the same direction. For example, the surface of the menuobject 60 on which the options 62 of “A1” to “A4” are disposed isassociated with the surface of the menu object 32 on which the option 34of “A” is disposed. Furthermore, the surface of the menu object 60 onwhich the options 62 of “A1” to “A4” are disposed and the surface of themenu object 32 on which the option 34 of “A” is disposed are oriented inthe same direction. In the present embodiment, the options 62 disposedon the menu object 60 are subcategories of the option 34 of thecorresponding surface in the menu object 32 for example. Furthermore, inresponse to operation of selecting any of the displayed options 62,processing according to the selected option 62 is executed.

Suppose that, from the state in which the head of the user is disposedat the position P14 as shown in FIG. 11, the head of the user movesrearward from the position P14 to a position P16 along a route R14 forexample. In this case, the point 30 of view moves rearward from theposition P3 to a position P18 along a route R16 as shown in FIG. 13.Then, the menu object 32 disposed in the virtual three-dimensional spacechanges to three menu objects 64 shown in FIG. 13. This leads todisplaying of the menu objects 64 on the display unit 26 as shown on thelower side of FIG. 14. As just described, the number of objects disposedin the virtual three-dimensional space may change according to change inthe distance between the point 30 of view after movement and the objectdisposed in the virtual three-dimensional space.

The three menu objects 64 shown in FIG. 13 are each a hexahedron. Anoption 66 is disposed on each surface of the menu objects 64. In thepresent embodiment, the options 66 disposed on the surfaces of the menuobjects 64 are higher-level categories of the option 34 disposed on thecorresponding surface of the menu object 32 for example. Furthermore, inresponse to operation of selecting any of the displayed menu objects 64,processing according to the option 66 disposed on the selected menuobject 64 is executed.

The above configuration enables the user to change the displayed objectand the selectable options by moving the head forward or rearward.

The range in which the point 30 of view can move may be limited.Specifically, the distance between the point 30 of view and the menuobject 32 may be limited to a predetermined range for example.

A further description will be made below with reference to FIG. 15 aboutone example of change of the menu object 32 according to the distancebetween the point 30 of view and the menu object 32 and the limitationof the range in which the point 30 of view can move.

The following description is based on the assumption that the distancebetween the point 30 of view and the menu object 32 in the initial stateis d0. In the present embodiment, the distance between the point 30 ofview and the menu object 32 refers to the distance between the positionof the point 30 of view and the position of a representative point ofthe menu object 32, specifically e.g. the distance between the positionof the point 30 of view and the position of the center of the menuobject 32.

Here, for example, the range in which the point 30 of view can move maybe limited to a point-of-view movable range exemplified in FIG. 15, inwhich the distance between the point 30 of view and the menu object 32is at least dmin and at most dmax (here, dmin<d0<dmax). That is, thedistance between the point 30 of view and the menu object 32 may becontrolled not to become shorter than dmin and not to become longer thandmax.

As shown in FIG. 15, the ranges of the distance in which the menu object32 changes to the menu object 60 or the menu objects 64 may be set inthe present embodiment. In the example of FIG. 15, if the distancebetween the point 30 of view and the menu object 32 is at least dmin andat most d1, the menu object 32 changes to the menu object 60 and themenu object 60 is displayed (here, dmin<d1<d0). If the distance betweenthe point 30 of view and the menu object 32 is at least d2 and at mostdmax, the menu object 32 changes to the menu objects 64 and the menuobjects 64 are displayed (here, d0<d2<dmax). If the distance between thepoint 30 of view and the menu object 32 is longer than d1 and shorterthan d2, the menu object 32 is displayed.

In the present embodiment, when the posture of the HMD 10 becomes theposture of the initial state, the position and the direction of the lineof sight of the point 30 of view may become the initial state and themenu object 32 may be displayed.

Displayed contents may be gradually changed to display appearanceobtained when the object disposed in the virtual three-dimensional spaceis viewed from a base relative position, specifically e.g. a relativeposition in the initial state. For example, when the point 30 of viewrevolves, the menu object 32 may gradually rotate into the orientationwith which the option 34 of “A” is visible in such a manner as to followthe revolution of the point 30 of view.

One example of processing of the gradual rotation of the menu object 32will be described with reference to FIG. 16. FIG. 16 is a diagramshowing appearance obtained when the virtual three-dimensional spaceshown in FIG. 3 is viewed from above, i.e. viewed along the Z-axisnegative direction. In the example shown in FIG. 16, the orientation ofthe menu object 32 is decided on the basis of the moving average of theposition coordinates of the point 30 of view. Here, for example, supposethat the position of the point 30 of view identified in a certain frameis Pa (x1, y1, z1) as shown in FIG. 16. Furthermore, suppose that theposition of the point 30 of view identified in the frame immediatelyprevious to the relevant frame is Pb (x2, y2, z2). Similarly, supposethat the positions of the point 30 of view identified in the framesprevious to the relevant frame by two frames, by three frames, and byfour frames are Pc (x3, y3, z3), Pd (x4, y4, z4), and Pe (x5, y5, z5),respectively. The average of the coordinates of the position Pa, theposition Pb, the position Pc, the position Pd, and the position Pe isidentified as the coordinates of a position Pf serving as the basis ofthe orientation of the menu object 32. Here, the position Pf((x1+x2+x3+x4+x5)/5, (y1+y2+y3+y4+y5)/5, (z1+z2+z3+z4+z5)/5) isidentified for example. Furthermore, for example, the menu object 32rotates so that the surface on which the option 34 of “A” is disposed asthe base surface of the menu object 32 may become perpendicular to aline segment linking the position Pf and the position P0 of the point 36of gaze, which is also the position of the center of the menu object 32.

This allows the user to rotate the menu object 32 by rotating the HMD10. Furthermore, movement of the menu object 32 according to movement ofthe HMD 10 in a similar manner may be allowed.

The processing of the gradual rotation of the menu object 32 is notlimited to the above-described processing. For example, the orientationof the menu object 32 does not need to be decided on the basis of themoving average of the position coordinates of the point 30 of view.Furthermore, for example, a position on a circle centered at theposition P0 of the point 36 of gaze may be identified as the positionPf.

Furthermore, e.g. a configuration may be employed in which the displayedimage does not change even when the HMD 10 rotates or moves during aperiod when the user is carrying out limitation operation such asoperation of pressing down a predetermined button. This allows the userto rotate and move the head without changing the displayed contents.Therefore, for example, when taking a hard posture, the user can returnthe posture to a natural posture without changing the displayedcontents.

Moreover, for example, when the user carries out reset operation such asoperation of pressing down a predetermined button, the displayedcontents may change to a state in which appearance obtained when theobject is viewed from the base relative position is displayed, such asthe above-described initial state.

The point-of-view control section 44 shown in FIG. 9 may carry out thechange of the menu object described with reference to FIGS. 11 to 15 andthe rotation of the menu object described with reference to FIG. 16.Furthermore, the point-of-view control section 44 may carry out controlto limit the distance between the point 30 of view and the object withinthe predetermined point-of-view movable range as described withreference to FIG. 15.

Furthermore, during a period when limitation operation is received, thedisplay control section 48 may limit change in the image displayed onthe display unit 26 irrespective of whether rotation is detected by thedetecting section 42.

What are described above can be applied to both the case in whichtwo-dimensional images are displayed on the display unit 26 and the casein which three-dimensional images are displayed on the display unit 26.In the case in which three-dimensional images are displayed, theabove-described processing is executed about each of the point 30 ofview associated with an image for the left eye and the point 30 of viewassociated with an image for the right eye.

The present disclosure is not limited to the above-described embodiment.

For example, an embodiment of the present disclosure may be applied to adevice other than the HMD 10. For example, an embodiment of the presentdisclosure may be applied to a computer such as a portable game deviceheld by a user, with a display disposed in front of the eyes of theuser. Furthermore, an embodiment of the present disclosure may beapplied to a portable computer that is fitted to a casing worn by a userso as to cause a display to be disposed in front of the eyes of theuser. Moreover, for example, an information processing device that cancommunicate with the HMD 10, such as an entertainment device, may carryout the above-described control. For example, an information processingdevice that can communicate with the HMD 10 may carry out control tocause the display unit 26 to display an image representing appearanceobtained when an object is viewed from the point of view that hasrelatively revolved in the direction of detected rotation while theposition of the point of gaze is kept in response to detection of therotation of the HMD 10.

The present disclosure contains subject matter related to that disclosedin Japanese Priority Patent Application JP 2015-112591 filed in theJapan Patent Office on Jun. 2, 2015, the entire content of which ishereby incorporated by reference.

What is claimed is:
 1. A head-mounted display that displays an imagerepresenting appearance obtained when an object is viewed from a pointof view disposed in a virtual three-dimensional space, the head-mounteddisplay comprising: a detecting section configured to detect rotation ofthe head-mounted display; and a display control section configured tocarry out control to cause displaying of an image representingappearance obtained when the object is viewed from the point of viewthat has relatively revolved in a direction of the detected rotationwhile a position of a point of gaze is kept in response to the detectionof the rotation by the detecting section.
 2. The head-mounted displayaccording to claim 1, wherein the display control section carries outcontrol to cause displaying of an image representing appearance obtainedwhen the object is viewed from the point of view that has relativelyrevolved in a direction of the detected rotation while the position ofthe point of gaze and distance to the object are kept in response to thedetection of the rotation by the detecting section.
 3. The head-mounteddisplay according to claim 1, wherein the detecting section also detectsmovement of the head-mounted display, and the position of the point ofgaze relatively moves in response to the detection of the movement bythe detecting section.
 4. The head-mounted display according to claim 3,wherein the object changes according to change in distance between thepoint of view resulting from movement and the object.
 5. Thehead-mounted display according to claim 1, wherein the display controlsection gradually changes displayed contents to display appearanceobtained when the object is viewed from a base relative position.
 6. Thehead-mounted display according to claim 1, wherein the display controlsection limits change in a displayed image irrespective of whetherrotation is detected by the detecting section during a period whenlimitation operation is received.
 7. The head-mounted display accordingto claim 1, wherein options are disposed on surfaces of the object, andthe head-mounted display further comprises a processing executingsection configured to execute processing according to the optiondisposed on a displayed surface of the object in response to acceptanceof selection operation.
 8. An information processing device thatdisplays an image representing appearance obtained when an object isviewed from a point of view disposed in a virtual three-dimensionalspace, the information processing device comprising: a display controlsection configured to carry out control to cause displaying of an imagerepresenting appearance obtained when the object is viewed from thepoint of view that has relatively revolved in a direction of detectedrotation while a position of a point of gaze is kept in response todetection of the rotation.
 9. A display control method for displaying animage representing appearance obtained when an object disposed in avirtual three-dimensional space is viewed from a point of view disposedin the virtual three-dimensional space, the display control methodcomprising: detecting rotation; and carrying out control to causedisplaying of an image representing appearance obtained when the objectis viewed from the point of view that has relatively revolved in adirection of the detected rotation while a position of a point of gazeis kept in response to the detection of the rotation.
 10. A program fora computer which displays an image representing appearance obtained whenan object disposed in a virtual three-dimensional space is viewed from apoint of view disposed in the virtual three-dimensional space, theprogram comprising: by a detecting section, detecting rotation; and by adisplay control section, carrying out control to cause displaying of animage representing appearance obtained when the object is viewed fromthe point of view that has relatively revolved in a direction of thedetected rotation while a position of a point of gaze is kept inresponse to the detection of the rotation.